SR&D | Model 1 Power Soak Tom Scholz Amp Attenuator

Though the creative force behind the rock group Boston, Tom Scholz had an engineering problem. Because of the limitations of mid-1970s guitar-processing equipment, he couldn’t quite get the majestic rock music sound swirling around in his head to translate easily to tape.

In order to get the distorted, overdriven power-rock sound out of a guitar amplifier, technicians were saddled with recording then-state-of-the-art tube amps at maximum volume to achieve the desired “heavy” effect. Scholz found that technique to be less than elegant, so in true engineering form, he addressed the problem with an ingenious end-around.

Placing a series of resistors between the output of a high-level (100-W) tube amp and a speaker cabinet, Scholz found a way to “soak up” an amp’s output – though it could still be pinned at maximum volume, for full distortion effect. He had created what he called the Power Soak.

The first crack – Early versions of the Power Soak had settable input and output impedance’s and a rotary knob on the front that allowed a player to dial the volume down. Though the amplifier could crank out at 100 W, a player could actually plug headphones into the amp and play at a comfortable level. Scholz’s company, SR&D, released the invention publicly in 1980.